#include <iostream>
#include <cmath>

using namespace std;
int main() {
    //已知圆柱体的半径和高，求圆柱体的体积
    const float  PI = 3.14f; //定义了一个float类型的常量
    float radius = 4.5f;
    float height = 90.0f;
    double  volume = PI * pow(radius, 2) * height;
    cout << "体积是：" << volume << endl;

}
